Quote Originally Posted by Elon Gane
When I take pictures of something that has slope to it like grass at a low angle. The center is sharp but there is really nothing in focus on the left&right side.

Quote Originally Posted by HDNitehawk
If your shooting the 200mm at a close distance at f/2.8 your DOF is going to be very narrow. I think it would be more reasonable to test on a flat object to see if it has this OOF problem.

Here's an example a shot like you describe (grass shot low to the ground), and of whatHDNitehawk is talking about (thin DoF), shot with a 7D andEF 70-200mm f/2.8<span style="color: #ff0000;"]LIS II at 200mm, 1/30 s, f/2.8, ISO 1600 (for me, it's a nice demonstration of the power of IS and f/2.8, since I snapped this in my yard almost 30 minutes after sunset, when I could already see stars overhead). But with f/2.8 and focusing reasonably close (but not close enough to scare off the bunny), the DoF is very thin. Still, you can see a plane of focus which includes the bunny's eye and nose (but the whiskers on both sides extend out of the DoF - that's how thin it is). Note the thin line of grass that's in focus from one side of the frame to the other, on a slight diagonalrunning parallel to the angle of the bunny's head.


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I'll echoHDNitehawk's suggestion of trying the test shooting a flat subject (e.g. tape a piece of paper with text to the wall and shoot it straight on from a tripod).


Hope that helps...


John